1. Field of the Invention
This invention relates to a cleaner device for a peripheral storage device. More particularly, the invention relates to a cleaner cartridge allowing for the use of a compressed gas to clean the objective lens and other internal optical and mechanical components of an optical disk drive.
2. Description of the Related Art
Data processing systems require means for storing user data and instructions for manipulating such user data. One type of storage is main memory, which typically includes one or more integrated circuit microchips. Although the cost per unit of storage in the form of microchips has been trending downward, it is nevertheless expensive to use main memory as the exclusive form of storage. Thus, peripheral storage devices are also used.
The most common peripheral storage devices are magnetic recording units, such as magnetic tape drives and magnetic direct access storage devices (DASDs), and optical disk drives. These devices require mechanical motion to store and retrieve data. Mechanical motion is required to position a specific, desired portion of a tape or disk adjacent to a transducing head. The requirement for mechanical motion prevents peripheral storage devices from operating at the purely electronic speeds of main memory. However, because peripheral storage devices can store information more cheaply than main memory, such devices are nevertheless used to store certain less infrequently accessed information.
Peripheral storage devices are susceptible to contamination problems. Contamination results from several primary sources. First, contamination results from the removable nature of most peripheral storage media. Magnetic floppy disks, magnetic tapes, and optical disks are generally removable from their associated drives in the form of a cartridge and collect dust, dirt, vapor residues, and other miscellaneous forms of contaminants while exposed to the normal room environment. Upon the insertion of a cartridge into a drive, some of these contaminants may be transferred to the internal drive components. In addition, the cartridge access door in a drive (for the insertion and removal of storage media cartridges) allows for airborne contaminants to penetrate therein.
Another source of contamination is the contact made between moving parts of the drive, and between parts of the drive and the storage media. In magnetic tape drives, the tape contacts the tape head and other tape path components, creating particulates as the tape wears. The same is true for magnetic disks and heads in magnetic disk drives. All magnetic and optical drives include moving parts for the relative positioning of a storage medium and a transducing head. The mechanical action of and between these parts generates particulates. An additional source of contamination is airborne particulates, which may enter a drive via the cartridge access door, or by fan-forced air flow used for the cooling of system components.
Contaminants result in the degradation of performance of peripheral storage devices. In magnetic tape drives, contaminants can abrade the head and tape, decreasing the effectiveness. Also, contaminants can separate the tape and head, resulting in magnetic drop-out (signal loss). The same is true for magnetic disk drives, in which the crash of a head into a simple dust particle can result in catastrophic failure of the drive. Optical disk drives are different from magnetic drives in that various contamination sensitive components of the optical beam path are not located immediately adjacent to the storage media. Optical disk drives have a mode of susceptibility to contaminants in addition to those of magnetic drives - contaminants disrupting a portion of the optical beam path can also have a negative impact on performance. For example, the scattering, deflection, or blockage of the optical beam can prevent accurate reading and writing of data.
Just as different contamination problems are associated with each type of peripheral storage device, there are cleaning techniques having various levels of effectiveness, some associated with a specific type of peripheral storage device. Several techniques are known for removing contaminants from the internal components of a peripheral storage device. One technique is to remove the outside housing of the drive to gain access to and clean all contaminated internal drive components. However, this technique is timely, and generally requires the assistance of a trained technician to properly disassemble the drive, clean the appropriate components, and reassemble the drive. Another technique is the use of mechanical brushing or wiping action through the cartridge access door of a drive. Such mechanical action is provided manually by operator insertion of a cotton swab through the cartridge access door of the drive. This technique is not preferred because the access door does not usually provide adequate access to all of the internal drive components requiring periodic cleaning. In cases where adequate access is provided, such access is nevertheless awkward, difficult for the operator to perform, or risks damage to the internal components of the device.
Another technique for cleaning the internal components of a peripheral storage device is the mounting of a brush, pad or similar device for contact cleaning on or in a cartridge housing. The brush is brought into contact with the components to be cleaned, usually the transducing head, during or after insertion of the cleaning cartridge into the drive. A brush mounted on a cartridge may be swept across a component as the cartridge is inserted into the drive and finally positioned relative to a magnetic or optical transducing head. Examples of such a cartridge for cleaning an objective lens in an optical disk drive are disclosed in U.S. Pat. No. 4,870,636 and Japanese published unexamined patent applications 63-244467, 02-49284, and 02-168481. A brush mounted in a cartridge is swept across a component after the cartridge is finally positioned relative to the transducing head. In magnetic tape drives, it is well known to use a cartridge having a special cleaner tape therein replacing the magnetic recording tape. The cleaner tape contacts the magnetic tape head(s) and tape bearing surfaces of the cleaner tape just as the recording tape would. The material used to manufacture the cleaner tape is designed to remove contaminants from the surfaces with which it makes contact. In disk drives, it is similarly known to use a cartridge having a special disk therein to clean a magnetic head or optical beam path objective lens. Examples of such a cartridge for cleaning a magnetic disk head in a magnetic disk drive are disclosed in U.S. Pat. Nos. 4,065,798, 4,503,473, and 4,663,686 and examples of such a cartridge for cleaning the objective lens of an optical disk drive are disclosed in U.S. Pat. No. 4,817,078 and Japanese published unexamined patent applications 63-209084 and 01-251482.
The aforementioned use of a brush or pad mounted on or in a cartridge is not optimal for cleaning optical disk drives. Because the objective lens of an optical disk drive is located relatively near to a cartridge therein (although still much farther than a magnetic head is, if at all, from a magnetic disk or tape cartridge), such a brush may be used to clean the objective lens. However, the remaining optical components of an optical disk drive cannot be so cleaned. Other lenses, mirrors, prisms, and detectors may be used in the optical beam path for focussing and/or tracking and are located further from the cartridge than the objective lens. There is no known technique for providing mechanical brushing or wiping of such internal components using a simple cleaning cartridge. Also, such mechanical action is not desired as these optical components tend to be more susceptible to degradation from scratching or brush streaks than magnetic heads.
Any of the aforementioned mechanical brushing or wiping techniques may be combined with the use of cleaning liquids applied to the brushes or pads of the cleaning device. Examples of the use of such cleaning liquids are disclosed in U.S. Pat. Nos. 4,558,386, 4,622,617, and 4,682,257. For optical disk drives, these combined cleaning techniques still suffer from those previously described drawbacks associated with mechanical action. To eliminate the abrasion caused by the mechanical brushing action itself, cleaning liquids may be used apart from such contact cleaning techniques. For example, U.S. Pat. No. 4,639,813 discloses a cleaning cartridge for a magnetic disk drive which allows for a cleaning liquid to be injected into the drive. Although mechanical abrasion is eliminated, it is difficult to ensure that the desired components are sprayed with the cleaning liquid, and that other components sensitive to moisture are not so sprayed.
Another non-contact technique for cleaning peripheral storage devices is the use of air flow. One technique is to manually insert a tube through the cartridge access door of the drive. The end of the tube outside of the drive is connected to a source of compressed gas, such as an aerosol can, and the end of the tube inside of the drive is aimed to direct the gas exiting therefrom at the internal drive component for which cleaning is desired. This technique suffers from the same disadvantages as those associated with the aforementioned manual mechanical brushing or wiping techniques. In another technique, a fan is mounted inside the drive and used to blow or pull air across the internal components of the drive. An example of fan-driven air flow to clean a magnetic disk drive is disclosed in Tollefson, Air-Jet Diskette Cleaner, IBM Technical Disclosure Bulletin, Vol. 26, No. 3A, August, 1983, pp. 1007-08 and an example of such in an optical disk drive is disclosed in Japanese published unexamined patent application 01-185840. Although such air flow has some potential benefit, it is inadequate in that it cannot be directed at specific drive component(s). Furthermore, the size and power constraints of the drive limit the air velocity which can be generated by the fan, thereby inhibiting cleaning ability. Finally, unless the air is adequately filtered, it may cause more contamination than it eliminates.
As the storage density of peripheral storage devices increases, the amount of contamination required to result in a negative impact on the performance of a peripheral storage device decreases. For example, the cross-section of the focussed spot in an optical disk drive determines the size of a recorded data bit. As the cross-section of the collimated optical beam is reduced, the size of a particulate required to fully block the beam and prevent read/write operations is thus also reduced. A heretofore unrecognized problem is how to clean a plurality of the internal components of a peripheral storage device without the drawbacks of the aforementioned cleaning techniques.